Pneumatic hammer



Oct. 27 31.

F. R. ROBINSON PNEUMATIC HA Filed Ma 6 929 ATTO Y 2 -Sheen l Oct. 27, 1931. F. R. ROBINSON PNEUMATIC HAMMER Filed May 6, 1929 2 Sheets-Sheen 2 INVENTOR BY M WATTORNEY Patented Oct 27 1931 FRANK R. ROBINSON, F PHILADELPHIA, PENNSYLVANIA PNEUMATIC HAMMER Application filed May 6, 1929. Serial No. 360,810.

The present invention relates to an improved pneumatic hammer, and it is the purpose of the present invention to provide a tool of this kind possessing two cylinders, one

having a chamber for a tool striking piston pneumatically actuated, the other having a chamber operatively connected with the first chamber at opposite remote points to the tool striking piston, said later chamber containing a piston to create pneumatic compression on one end of the tool striking piston, and to rarefy the air or create a vacuum in the first chamber on the opposite end of the tool striking piston, thereby imparting rapid consecu- 1 tive movements to the tool striking piston to cause hammer blows on the tool.

Another purpose is to provide a pneumatic hammer having means in the first chamber to cushion the tool striking piston on its rebound stroke.

Still another purpose is to provide a pneumatic tool of this kind having means for operating the piston in the second chamber.

It is to be understood that the particulars herein given are in no way limitative, and that while still keeping within the scope of the invention, any desired modification of details and proportions may be made in the construction of the appliance according to 0 circumstances.

The invention comprises further features and combination of parts to be hereinafter set forth, shown in the drawings and claimed.

In the drawings Figure 1 is a view in elevation of the improved pneumatic hammer constructed in accordance of the invention.

Figure 2 is a longitudinal sectional view 0 through the same more clearly showing the interior construction and arrangement of the parts. 7

Figure 8 is a cross sectional view on line 3-3 of Figure 2.

Figure 4 is a longitudinal sectional view through another form of pneumatic hammer, wherein the chamber for the tool striking piston is surrounded by a cylinder, which communicates with the first and second chambers.

Figure '5 is a cross sectionalview on line 55 of Figure 4.

Referring to the drawings, 1 identified a' cylinder having a compartment 2 for a high speed electric motor 3, which may be furnished with current from any suitable source not shown. The shaft 4 of themotor has a gear- 5 meshing with agear 6 on a worm 7, which meshes with a worm wheel 8 on a transverse shaft 9. This transverse shaft 9 6 carries an eccentric 10, to which. a link 11 is connected, the link being in turn connected to; a'rod 12 operating through a bearing '13. The rod 12 carries a piston 14, which. reciprocatesin the chamber 15. g

The chamber 15 communicates, by way of a passage 16 with a chamber 17, which is formed in the cylinder 18.. This cylinder 18 carries a tool striking'hammer 19, to impart hammer blows to the tool 20.

One end of the chamber 17 communicated, by means of a tube 21 in Figures 1, 2 and 3 and by means of a cylinder 22 in Figures 4 and 5 with the chamber 15. This tube 21 or cylinder 22 rarefies or creates a vacuum on one side of the piston 14 to create a suction on one end of the piston 19, While a compression action is created on the one side of the piston 14, in order to impart increased power on the tool striking piston 19. The chamber 17 at one end has a compression spring 23, supported on a lug 24, said compression spring acting to cushion the tool striking piston on its rebound stroke. A handle 25 is provided, whereby the pneumatic hammer may be supported when in use.

On the stroke of the piston 14 in the direction of the arrow A compressed air on one end of the piston 19 is applied, and a vacuum or a rarefication of air on the other end of the piston 19, thereby providing increased power on the piston 19. A reverse movement of the piston 14 reverses the action on the tool striking piston 19.

The chambers 17 and 22 have the usual check valves 17 a for taking care of the air in said chamber.

The invention having been set forth, what is claimed is:

In a pneumatic hammer, a pair of adjacent it 7 Q 1,829, 09

cylinders, a tool loose in and having limited movement in one end of one cylinder, apis- 7 ton hammer operative in the cylinder having a tool and adapted'for striking cooperation 5 Withthe tool, the other cylinder having a pressure chamber in communication with the r first cylinder adjacentthe ends of therpiston hammercyl inden said: other cylinder having i a compartment,'a piston operable in the pres 7 10 sure chamber and dapted for creating a11- compression oniones' sidezoi': thcgpistom Iner and for rarefying or creating a'vacuum on the opposite side of the pistonha' mnier, and a motor driven mechanism in said com 1 partment iior imparting movementto the? pis onin the pressure chamben,:, 1mi m a comprising check valves operative in com-' miuijcationwith the. interior: ofi thezfirstj cyl- 1 inder incident. to the compression and the.

202 rereficat'ionl ad jacent opposite of! the.

piston hammer; one of said check valveshei-r I ing located atthe: end ofthefirst cylinder re,-- mote. from 1" thetool, T said "piston, adapted to substantiallyoverride;the check 7 2n v l e remote f om the: t l 411 o-. Overri e o eij f h flont ui ib tions v between; other cylinder the, firs cyliir'nden, and m an inthe first cylindcr tourgethcpiston hammer-from overriidi-ng plb sit dn, ofifth e ree I V mote check valve and themdjpcenticommunileationb tween h fi t and I second; cyl nd In testimony whereof: he; aflixes I his signas. 

